Coordinated Pembrolizumab and High Dose IL-2 (5-in-a-Row Schedule) for Therapy of Metastatic Clear Cell Renal Cancer
Jonathan Alexander Chatzkel, Michael J. Schell, Jad Chahoud, Jingsong Zhang, Rohit K. Jain, Jennifer Swank, Steve Ludlow, Kristina Lombardi, Yesenia Lucas, Cortlin Croft, Jennifer Rembisz, Gigi Jameel, Mayer Fishman
Abstract
INTRODUCTION: The ligation of the interleukin-2 (IL-2) receptor and immune checkpoint blockade may each alter lymphocytes, thereby inducing regression in various cancers. Single agent objective response rates of 14% to 25% have been reported for usual schedule 14-dose-in-a-row IL-2 therapy of metastatic clear cell renal cancer (ccRCC), with a notable subset of responses being durable. Pembrolizumab yielded a 33% response rate in patients with metastatic ccRCC. PATIENTS AND METHODS: This study addressed the safety and feasibility of the combination of IL-2 and pembrolizumab in the treatment of metastatic ccRCC. Subjects were treated with four 9-week blocks of therapy, receiving pembrolizumab every 3 weeks in all blocks and receiving 4 courses of 5-planned-doses high dose IL-2 in each of blocks 2 and 3. Safety was monitored by a Pocock boundary of study suspension and re-evaluation if exceeding a 15% dose limiting toxicity rate at α = 0.05. The Simon 2-stage design tested for an alternative hypothesis response rate of at least a 45% vs. a null hypothesis rate of less than 20%, with α = 0.10 and 90% power RESULTS: No accrual suspension for safety was triggered. The objective response rate was 70% (19/27, 95% CI: 0.50-0.86). Nine patients responded after pembrolizumab alone and ten responded after the addition of IL-2. At a minimum follow-up of 23 months, 9 of the responding patients had no disease progression requiring additional treatment. CONCLUSION: The combination of 5-planned-dose-schedule high dose IL-2 and pembrolizumab is feasible, with a high response rate, justifying further exploration of this dual immune treatment of metastatic ccRCC.